1. Field of the Invention
The present invention relates to the field of pendulum driven clocks and in particular, relates to mechanisms which include means for self-adjusting the driving member of the escapement in response to misalignments of the clock mechanism with respect to the vertical.
2. Description of the Prior Art
As is well known in pendulum clocks, the periodic oscillation of the pendulum bob is used as the time keeping or regulating device. Such clocks have proven to be very efficient, reliable, simple and accurate when used as stationary wall clocks. Thus, such clocks, despite the age of their basic design are still widely accepted and employed. However, pendulum clocks still suffer from at least one major shortcoming. In order to obtain accurate and reliable time keeping operation, the clock must be installed and aligned along a designed orientation with respect to the vertical as defined by gravity. This condition arises for the most part from the operational characteristics of the escapement mechanism. For example, in conventional pendulum clocks, the relative position of the pendulum bob or pendulum arm and the anchor of the escapement mechanism are designed to assume a neutral or equilibrium position when the designed vertical of the excapement mechanism is aligned along the vertical as defined by gravity. The escapement mechanism operates in an optimum fashion when the pendulum clock is installed such that the designed vertical lies parallel to the gravitational vertical. When such an alignment occurs, the escapement mechanism operates with a minimum amount of error and a maximum degree of reliability. In this case, the anchor or ratchet of the escape wheel is in its proper escapement position.
However, if a conventional pendulum clock is installed in a position which is misaligned with the gravitational vertical, the equilibrium position of the pendulum arm or bob is aligned along an axis which is nonparallel to the designed vertical of the escapement mechanism. The motion of the pendulum bob in this case causes the anchor to oscillate in a nonsymmetrical fashion. In this improper positioning, the anchor will execute a periodic oscillation with respect to its corresponding escape wheel with a perturbation which is directly proportional to the angle of inclination between the designed vertical and the gravitational vertical. This perturbation is manifested as a change in the degree of engagement between the pallet pins of the anchor and the escape wheel. This perturbation, or improper engagement, is known as anshor sideswing and is a chief factor in time keeping inaccuracy in pendulum regulated clocks. In the extreme case, the improper engagement between the anchor and escape wheel may cause the escape mechanism to fail and cease keeping time. Understandably, such an extreme case results in a complete and functional failure of the pendulum clock.
Furthermore, another defect in conventional pendulum clocks is the vulnerability of the pallet pins to relatively mild shocks. Any undue stress exerted upon the pallet pins may either bend or break one or more of the pallet pins when the pallet pins strike the escape wheel with excessive force. Such an event may occur either due to anchor sideswing or when the pendulum is given a strong pull in order to start the periodic motions of the clock. Bending or breaking of the pallet pins may also be caused by erratic oscillation of the pendulum due to vibration or impulsive changes in speed when the clock is shipped or moved.
Therefore, what is needed is a means for overcoming each of the prior art shortcomings, to wit, a pendulum clock mechanism which will accurately keep time even though the designed vertical is misaligned with the gravitational vertical; which damage to the pallet pins is substantially prevented by reducing the stress or shock applied to the pallet pins; and which will be automatically self-adjusting to prevent anchor sideswing and damage during movement, starting, or shipment.